Abstract One of the best methods for identifying novel genes and mutations affecting embryonic development is forward genetic screening. However, these screens require a large number of animals to be screened to identify a single novel mutant due to the inefficiency of chemical mutagenesis. This project will use a CRISPR library generated from mRNA to limit the mutations to genes expressed in the tissue and time point of interest. We will test this method using both F0 and F2 cardiovascular screens for heart phenotypes in zebrafish, potentially providing several novel mutants for further study. In addition to the novel mutants identified in the screen, this method will be able to be adapted to any tissue in any species, reducing the resources needed to conduct forward genetic screens and increase the speed of gene discovery in a number of species and developmental processes.